In the fabrication of some structures such as aircraft, for example, it may be desirable to use composite panels due to the panels' high strength-to-weight ratio. Stiffening elements may be attached to the composite panels at various locations to reinforce and impart structural strength to the panels. These stiffening elements may include, for example, hat stiffeners; I-beams; blade stiffeners; honeycomb cores; and foam cores.
The conventional types of stiffening elements used to stiffen composite panels may have various disadvantages. For example, hat stiffeners may occupy a relatively large area on the panel and may require internal support for cure. I-beams may need to be fabricated from multiple pieces and may require complex tooling during cure to maintain their profile. Furthermore, the tooling may be difficult to remove after cure. Traditional blade stiffeners may not be as structurally efficient as other shapes. Honeycomb and foam core may be heavier and may have a tendency to be crushed during cure and to retain water in service.
What is needed is a modified blade stiffener having enhanced mechanical properties and a method of fabricating a modified blade stiffener which can be fabricated as a single piece without the use of fasteners.